(Last change to this page: 27 August 1998.)
Paul Sloane has popularized the term "lateral thinking puzzles" for this kind of game/puzzle. To me, a lateral thinking puzzle is a puzzle without a definite answer, to be approached by brainstorming to come up with a variety of different useful answers; whereas good situation puzzles have a clear definite best answer (even if there are other answers that fit the initial conditions). I agree, however, that situation puzzles can encourage lateral thinking (a term coined by Dr. Edward de Bono), in that they encourage taking unusual approaches to problem-solving, and questioning one's assumptions, and so on.
Nonetheless, as far as I'm concerned a good situation puzzle is one that plays well as a game (that is, that is enjoyable for all participants), not necessarily one that encourages thinking "outside the box." My favorite situation puzzles don't rely on misleading the audience or requiring specialized knowledge; my favorites are the ones that seem surprising, contradictory, or mysterious on the surface, and have a complicated backstory which questioners can gradually uncover through a process of questioning. Ideally there should be an "aha" experience on discovering the solutionbut the solution should not remain totally opaque before that "aha" experience, as it is in many traditional puzzles. In other words, if the answer to every intermediate question is likely to be "no, guess again," I think of it more as a riddle or a traditional puzzle than as a situation puzzle.